#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <mach/hardware.h>
#include <linux/platform_device.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>

#include <mach/map.h>
#include <mach/regs-clock.h>
#include <mach/regs-gpio.h>

#include <plat/gpio-cfg.h>
#include <mach/gpio-bank-n.h>
#include <mach/gpio-bank-l.h>

#define DEVICE_NAME     "buttons"

struct button_irq_desc {
	int irq;
	int number;
	char *name;
};

static struct button_irq_desc button_irqs[] = {
		{
				IRQ_EINT(0),
				0,
				"KEY0" },
		{
				IRQ_EINT(1),
				1,
				"KEY1" },
		{
				IRQ_EINT(2),
				2,
				"KEY2" },
		{
				IRQ_EINT(3),
				3,
				"KEY3" },
		{
				IRQ_EINT(4),
				4,
				"KEY4" },
		{
				IRQ_EINT(5),
				5,
				"KEY5" },
		{
				IRQ_EINT(19),
				6,
				"KEY6" },
		{
				IRQ_EINT(20),
				7,
				"KEY7" }, };
static volatile char key_values[] = {
		'0',
		'0',
		'0',
		'0',
		'0',
		'0',
		'0',
		'0' };

static DECLARE_WAIT_QUEUE_HEAD( button_waitq);

static volatile int ev_press = 0;

static irqreturn_t buttons_interrupt(int irq, void *dev_id) {
	struct button_irq_desc *button_irqs = (struct button_irq_desc *) dev_id;
	int down;
	int number;
	unsigned tmp;

	mdelay(15);
	number = button_irqs->number;
	switch (number) {
	case 0:
	case 1:
	case 2:
	case 3:
	case 4:
	case 5:
		tmp = readl(S3C64XX_GPNDAT);
		printk("temp:%d\n",tmp);
		down = !(tmp & (1 << number));
		printk("down:%d\n",down);
		break;
	case 6:
	case 7:
		tmp = readl(S3C64XX_GPLDAT);
		down = !(tmp & (1 << (number + 5)));
		break;
	default:
		down = 0;
	}

	if (down != (key_values[number] & 1)) {
		key_values[number] = '0' + down;

		ev_press = 1;
		wake_up_interruptible(&button_waitq);
	}

	return IRQ_RETVAL(IRQ_HANDLED);
}

static int s3c64xx_buttons_open(struct inode *inode, struct file *file) {
	int i;
	int err = 0;

	for (i = 0; i < sizeof(button_irqs) / sizeof(button_irqs[0]); i++) {
		if (button_irqs[i].irq < 0) {
			continue;
		}
		err = request_irq(button_irqs[i].irq, buttons_interrupt, IRQ_TYPE_EDGE_BOTH, button_irqs[i].name,
				(void *) &button_irqs[i]);
		if (err)
			break;
	}

	if (err) {
		i--;
		for (; i >= 0; i--) {
			if (button_irqs[i].irq < 0) {
				continue;
			}
			disable_irq(button_irqs[i].irq);
			free_irq(button_irqs[i].irq, (void *) &button_irqs[i]);
		}
		return -EBUSY;
	}

	ev_press = 1;

	return 0;
}

static int s3c64xx_buttons_close(struct inode *inode, struct file *file) {
	int i;

	for (i = 0; i < sizeof(button_irqs) / sizeof(button_irqs[0]); i++) {
		if (button_irqs[i].irq < 0) {
			continue;
		}
		free_irq(button_irqs[i].irq, (void *) &button_irqs[i]);
	}

	return 0;
}

static int s3c64xx_buttons_read(struct file *filp, char __user *buff, size_t count, loff_t *offp)
{
	unsigned long err;

	if (!ev_press) {
		if (filp->f_flags & O_NONBLOCK)
		return -EAGAIN;
		else
		wait_event_interruptible(button_waitq, ev_press);
	}

	ev_press = 0;

	err = copy_to_user((void *)buff, (const void *)(&key_values), min(sizeof(key_values), count));

	return err ? -EFAULT : min(sizeof(key_values), count);
}

static unsigned int s3c64xx_buttons_poll(struct file *file, struct poll_table_struct *wait) {
	unsigned int mask = 0;
	poll_wait(file, &button_waitq, wait);
	if (ev_press)
		mask |= POLLIN | POLLRDNORM;
	return mask;
}

static struct file_operations dev_fops = {
		.owner = THIS_MODULE,
		.open = s3c64xx_buttons_open,
		.release = s3c64xx_buttons_close,
		.read = s3c64xx_buttons_read,
		.poll = s3c64xx_buttons_poll, };

static struct miscdevice misc = {
		.minor = MISC_DYNAMIC_MINOR,
		.name = DEVICE_NAME,
		.fops = &dev_fops, };

static int __init dev_init(void)
{
	int ret;

	ret = misc_register(&misc);

	printk (DEVICE_NAME"\tinitialized\n");

	return ret;
}

static void __exit dev_exit(void)
{
	misc_deregister(&misc);
	printk("exit\n");
}

module_init( dev_init);
module_exit( dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("zekezang Inc.");
